In the graphics arts, it is often desirable to produce a four or more color proof from image data to assist a printer in correcting a set of color prints prior to using the image data to produce color plates and also to reproduce the color quality that will be obtained during the printing process. The proof must be a consistent duplication of the half tone image from a printing process, and should neither gain nor lose color in comparison to the printed image. Visual examination of a color proof should show the following characteristics:
1. defects on the negatives, PA1 2. best color rendition to be expected from press printing of the material, PA1 3. correct gradation of all colors and whether grays are neutral, and PA1 4. need, if any, for subduing one of the colors and/or giving directions for altering the film negatives before making the printing plates. Color proofing for multi-colored printing without the use of pre-press color proofs are made by using a printing press or a proof press taking all the steps necessary for actual multicolor printing. Such a conventional method of color proofing is costly and time consuming. PA1 (a) a flexible support base film; and PA1 (b) a colorant layer comprising a colorant and an alkali soluble photopolymer. PA1 (1) in sequential order, (a) a flexible support base film, Co) a colorant layer coated thereon, and (c) an oxygen barrier layer coated on the surface of the colorant layer, wherein the surface of the colorant layer is away from the base film; PA1 (2) in sequential order, (a) a flexible support base film, Co) an oxygen barrier layer situated between the base film and a colorant layer, (c) the colorant layer, wherein the base film has a release surface; PA1 (3) in sequential order, (a) a flexible support base film, (b) a colorant layer coated thereon, (c) a barrier layer, and (d) an adhesive layer, wherein the barrier layer protects the colorant layer from the adhesive layer and vice versa; PA1 (4) in sequential order, (a) a flexible support base film, Co) an oxygen barrier layer situated between the base film and a colorant layer, (c) the colorant layer, (d) a barrier layer to protect the colorant layer from an adhesive layer and (e) the adhesive layer, wherein the base film has a release surface; PA1 (5) in sequential order, (a) a flexible support base film, (b) a colorant layer, and (c) an adhesive layer; and PA1 (6) in sequential order, (a) a flexible support base film, (b) an oxygen barrier situated between the base film and a colorant layer, (c) the colorant layer, and (d) an adhesive layer. PA1 R.sup.1 can be represented by ##STR2## wherein m is 0 for --R.sup.1 --R.sup.4, and m is 1 for --R.sup.1 --R.sup.2 and --R.sup.1 --R.sup.3 ; PA1 n is 0 or 1; PA1 R.sup.6, R.sup.7, R.sup.8, and R.sup.9 can be independently an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 5 to 12 carbon atoms, an aryl or aralkyl group having 6 to 12 carbon atoms or at least one of the pairs R.sup.6 and R.sup.7, and R.sup.8 and R.sup.9, taken together with the carbon to which it is joined forms a 5- or 6-membered carbocyclic ring, or any of R.sup.6, R.sup.7, R.sup.8 and R.sup.9 may be H when n is 1; preferably R.sup.6 and R.sup.7 are methyl and n is 0; PA1 W can be --NH--, NR.sup.13, --S-- or --O--, wherein R.sup.13 can be alkyl of 1 to 12 carbon atoms; preferably W can be --O-- or --NH--; it is most PA1 R.sup.2 (m is 1) can be a polymerizable, ethylenically unsaturated group selected from PA1 R.sup.3 (m is 1) represents hydrogen, or a solubilizing cation such as sodium, potassium, or quaternary ammonium, or --E--A wherein E represents a divalent organic connecting group having up to a total of about 18 C, N, S, and nonperoxidic 0 atoms, and A is an acid group selected from carboxyl, sulfo, and phospho groups, and salts thereof. R.sup.3 may be multifunctional, having more than one group A. Non-limiting examples of E include alkylene and arylene groups (e.g., propane-1,3-diyl, methylene, dodecane1,12-diyl, p-phenylene), oxa-substituted alkylene groups (e.g., 2-oxapropan- 1,3-diyl, 3-oxapentan- 1,5-diyl), aza-substituted alkylene groups (e.g., 2-azapropan-l,3-diyl, 3-methyl-3-azapentan-1,5-diyl), and the like. Examples of A include, but are not limited to, carboxy group (--COOH), phospho group (--PO.sub.3 H.sub.2), and sulfo group (---SO.sub.3 H) and their salts with alkali metals (e.g., sodium, lithium, potassium), mono-, di-, tri-, and tetra-substituted ammonium salts (e.g., ammonium, tetrabutyl ammonium, phenyldipropylammonium). Preferably, A is a carboxyl group, sulfo group, or phospho group or an alkali metal or tetra substituted ammonium salt thereof. PA1 It is possible to incorporated the quaternary ammonium salt group into the polymer by reaction with the formed polymer via a coupling reaction (such as coupling through an azlactone group with a nucleophile substituted quaternary ammonium salt), or by quaternization of a tertiary amine bound to the polymer, it is also possible to copolymerize the photopolymer with a quaternary ammonium salt-containing monomer. It is also possible to incorporate a quaternary ammonium salt into the polymer via neutralization of the polymer after hydrolysis, thus replacing the carboxylate group (when R.sup.4 is --CO.sub.2 H) with tetrabutylammonium hydroxide or tetramethylammonium hydroxide. PA1 R.sup.4 (m is 0) represents --CO.sub.2 H and salts thereof, carboalkoxy group having from 2 to 40 carbon atoms, or a mono- or dialkylamido group having from 2 to 40 carbon atoms. Preferably R.sup.4 is --CO.sub.2 H and salts thereof. PA1 a, b, c, and d independently represent a ratio of a monomeric unit to the total number of monomeric units, such that the sum of a+b+c+d equals 1, alternatively, the sum of each of the percents of the single monomeric unit (represented by a, b, and c, and d) of the total number of monomeric units is equal to 100%; preferably a is 0.4-0.6, b is 0.1-0.4, c is 0.2-0.5, and d is 0-0.4, more preferably a is 0.5-0.6, b is 0.1-0.2, c is 0.4-0.5 and d is 0-0.2 PA1 Victoria Pure Blue (C.I. 42595) PA1 Auramine 0 (C.I. 41000) PA1 Cathilon Brilliant Flavin (C.I. basic 13) PA1 Rhodamine 6GCP (C.I. 45 160) PA1 Rhodamine B (C.I. 45170) PA1 Safranine OK70:10 (C.I. 50240) PA1 Erioglaucine X (C.I. 42080) PA1 Fast Black HB (C.I. 26150) PA1 No. 1201 Lionol Yellow (C.I. 21090) PA1 Shimura-Fast Yellow 8GF (C.I. 21105) PA1 Benzidine Yellow 4T-564D (C.I. 21095) PA1 Shimura-Fast Red 4015 (C.I. 12355) PA1 Lionol Red 7B 4401 (C.I. 15850) PA1 Fastogen Blue TGR-L (C.I. 74160) PA1 Lionol Blue SM (C.I. 26150) PA1 Mitsubishi Carbon Black MA-100 PA1 Mitsubishi Carbon Black #40 PA1 J is selected from a carbon-carbon bond, oxygen, sulfur, ##STR6## wherein R.sup.17 can be aryl (e.g., 6 to 20 carbon atoms) or acyl (e.g., 2 to 20 carbon atoms), R.sup.18 and R.sup.19 can be independently selected from hydrogen, alkyl groups of 1 to 4 carbon atoms, and alkenyl groups of 2 to 4 carbon atoms, PA1 D.sup.- can be any anion, preferably a complex metal halide such as hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate, etc. PA1 (1) thermal laminability at a temperature below 200.degree. C., preferably between 100.degree. to 160.degree. C., at a pressure of 1.6 lb/in.sup.2 (0.29 kg/cm.sup.2), PA1 (2) non-tacky at room temperature or preferably not laminable to paper or self-laminable at 45.degree. and 60.degree. C., 2 g/cm.sup.2, for at least one week, PA1 (3) will not discolor or alter its optical density by more than 0.05 optical density units when an area of 15,000 cm.sup.2 is exposed to a 5 kW source of UV radiation having a majority of the radiation distributed over the range of 350 and 450 nm, at a distance of 1 meter for 2 minutes, and PA1 (4) have no ingredients which by themselves or in combination with the solvent of the adhesive layer migrate across a barrier layer and desensitize the colorant layer, alter the color or tone of the pigments, or alter the optical qualities of the barrier or colorant layer.
Photographic processes are known that use photopolymers. There are various types of photographic color proofing methods, for example, the surprint type (laminated single sheet) and the overlay type.
In the overlay type of color proofing method, an independent transparent plastic support is used for producing a print of each color separation film by applying a photosensitive solution of the corresponding color. A plurality of such supports carrying prints of corresponding colors are then superposed upon each other on a white sheet to produce a color proof. The primary advantage of overlay type of color proofing is that it is quick and can serve as a overlay proof by combining at least colors in register.
In the surprint (adhesively laminated single sheet construction) type of color proofing method, a color proof is prepared by successively producing prints of different colors from different color separation films, respectively, by applying a photosensitive solution or coatings of photopolymers of corresponding color on the opaque support in succession. Alternatively, each color separation can be prepared by applying a photosensitive solution or coating of photopolymers of corresponding color to strippable support base film and then adhesively laminating the separate color prints together, in register, to prepare a full color proof. Some examples are described in U.S. Pat. Nos. 3,671,236 and 3,136,637. An advantage of this surprint type of color proof is that the color saturation is not influenced by the plastic support. This method more closely resembles the actual printing process and eliminates the color distortion inherent in the overlay system.
In addition to overlay or surprint types of color proofing, other processes for producing copies of an image embodying a photopolymerization and thermal transfer techniques are known. Some examples are described in U.S. Pat. Nos. 3,060,023, 3,060,024, 3,060,025, 3,481,736, and 3,607,264. Generally, in these processes, a photopolymerizable layer coated on a suitable support is exposed, imagewise to a process transparency. The surface of the exposed layer is then pressed into contact with the image receptive surface of a separate element and at least one of the elements is heated to a temperature above the transfer temperature of the unexposed portions of the layer. The two elements are then separated, whereby the thermally transferrable, unexposed image areas of the composition transfer to the image receptive element. If the element is not precolored, the tacky unexposed image may now be selectively colored with a desired toner. The colored matter adheres, preferentially, to the clear unpolymerized material. Since lamination, exposure and development are carried out for the respective colors, in sequence, these processes are generally time consuming.
Typically, the proofing constructions add an oxygen barrier between the support base film and the colorant layer. However, such barriers can fracture along the edges of the transparent sheet, or along the peel front, thus permitting entry of oxygen. The oxygen prohibits photopolymerization. Furthermore, several barriers are susceptible to water damage and render the construction ineffective and non-functional.